Did anyone actually stop to consider that when you hook your x10 camera up to the VCR... all they have to do is steal the VCR and suddenly all evidence disappears?
The best solution, monitoring wise, is to hook the cam up to an old PC and have it upload pics to the net, maybe every 4 to 6 seconds. That way they could empty the house but you'd still have evidence... heymatty is right on the ball, tracking devices are a good idea.
If I was going away for only a few days, I'd leave the dog at home and have a member of family come around a few times per day to feed it, fill up it's water bowl, let it out to shit, etc. Unless it would tear the house apart, it is a reasonable thing to consider.
There are also those motion sensoring devices that can be set to bark like a crazed dog whenever they sense movement... alslo, there are the devices that plug into the electrical outlet with a light attached, and can be set to turn the lights on and off at any time of the day or night, giving the impression that someone is home.